1. Field of the Invention
The present invention relates to a content distribution method of distributing a content such as a document, graphic, or video and a content distribution package which contains a content as a distribution target and is distributed from a content distribution apparatus to a terminal of a content distribution destination.
2. Description of the Related Art
Along with the recent increase in transfer rate, mass storage digital contents (to be simply referred to as contents hereinafter) formed by digitizing books and newspaper can be transmitted/received in a short time through the Internet.
Hence, content distributors download mass storage contents such as books and newspaper to information terminals (client terminals) including personal computers (PCs) of intending purchaser through the Internet. In this case, a content created by various kinds of document, graphic, or video creation software is downloaded to client terminals while being inserted in a package together with metadata. The client terminal expands the downloaded content by using expansion software corresponding to the creation software which has created the content. The document, graphic, or video of the expanded content is output and displayed on a display device.
The content distributors also write mass storage contents such as books and newspaper on storage media such as CD-ROMs and memory cards and sell them to customers in stores. A user (customer) of a portable information terminal (personal digital assistants: PDA) which has no communication function or, even if it has the function, does not use it inserts a purchased storage medium such as a memory card in the portable information terminal and reads out the content stored in the storage medium into the portable information terminal. By the same process procedures as in the above-described client terminal such as a PC, the expanded content is displayed on the display device of the portable information terminal.
In such a content distribution method, sometimes, encrypted contents are distributed (sold) to customers in order to surely collect the fees of distributed (sold) contents and ensure safety (security) of contents to be distributed (sold) to terminals. In this case, the client terminal or the user (customer) of the portable information terminal must acquire a key to decrypt the encrypted contents from the content distributor for pay or free. Generally, when the content is free, the key is chargeable. When the content is chargeable, the key is free.
However, even the above-described content distribution method still has the following problems to be solved.
Document, graphic, or video creation software to create contents is frequently upgraded to improve or add functions. Every time the software is improved, the revision number (version No) is updated. Generally, a revision number which changes on the integer basis indicates that the creation software is updated. A revision number which changes in decimal places indicates that functions are added to the creation software.
When creation software to create contents is upgraded, expansion software to expand the contents in a terminal held by a customer must also be modified in accordance with the modification of creation software.
Generally, information terminals such as PCs or portable information terminals held by customers often incorporate expansion software of the latest version at that time in correspondence with the above-described creation software. Alternatively, after an information terminal is purchased, expansion software is downloaded in it for pay or free through a network.
However, the customer has no means to know when the creation software and expansion software should be revised (upgraded). He/she is informed on the display screen that the expansion software stored in his/her information terminal such as a PC or portable information terminal needs update or addition for the first time when he/she has acquired a new content and key and is going to see the document, graphic, or video of the content.
In this case, update data or additional data for the expansion software must be acquired through the network to update or add the expansion software. The work of acquiring update data or additional data for expansion software and updating or adding the expansion software is very cumbersome for the customer and also takes a long operation time. In addition, the work is very burdensome to a customer who is unaccustomed to the operation of the information terminal.
A customer who uses a portable information terminal which has no communication function or, even if it has the function, does not use it must acquire update data or additional data for expansion software by a means other than the network. In some cases, a long time is required to acquire.
As described above, even when a customer who uses an information terminal acquire a content and key for pay, he/she is sometimes unable to see the document, graphic, or video of the content immediately and unconditionally.